Article
Monitoring HIV tropism and Maraviroc regimens in clinical routine – 48 weeks of follow-up data
HIV Tropismus und Maraviroc Regime in der klinischen Routine – 48 Wochen Daten
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Published: | June 2, 2010 |
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Background: Prior to initiating therapy with Maraviroc, the knowledge of the patients' viral tropism is crucial. The focus of this evaluation (11/2007–01/2010) was to prove the practicability of HIV tropism prediction and consequently therapeutical success of Maraviroc regimens in clinical routine.
Methods: The HIV-1 V3-loop region was sequenced before start of therapy. HIV coreceptor tropism was interpreted by geno2pheno. R5 results were accepted with a false-positive X4-rate of 20%. In addition, phenotypic tropism testing was performed by using Monograms Trofile™-Assay. 59 heavily pre-treated patients with CCR5-positive tropism received a Maraviroc containing regimen as follow-up therapy with an active drug score of 1.66 to 6 (HIV-Grade ver.07/2008). Therapy success (viral load ≤40 copies/ml) and possible changes in viral tropism were monitored at week 12–24 and 48.
Results: 34 paired tropism results were available. Discordant viral tropism results occurred in 5 of them (14.7%) patients between genotypic and phenotypic assays before start of Maraviroc therapy. While Trofile predicted a CCR5 tropism in these cases based on phenotypic data, geno2pheno predicted exclusively CXCR4 tropism. Therapies failed in two of these patients before week 24, despite an active drug score of 2-3. 45 patients reached week 48. 4 patients were lost to follow up. Two patients with failing therapies also experienced coreceptor tropism switch to CXCR4. After week 48, 34 of 45 patients (75.6%) had a viral load ≤40 copies/ml. The mean CD4-count increased from 435±258 to 554±262 cells/µl (N=45).
Conclusions: Combining Maraviroc together with further active drugs, is an effective option in clinical practice for heavily pretreated patients. Good treatment response was observed which might also be due to combinations of new drugs, documented by the high active drug scores. Generally genotypic analysis were conducted in Germany.